CSV File Cleaner
Drop a CSV file, trim whitespace, drop empty rows, remove duplicates and normalise line endings — all in your browser.
Quick answer: Drop a CSV file, trim whitespace, drop empty rows, remove duplicates and normalise line endings — all in your browser.
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Frequently asked questions
- Does this CSV cleaner upload my file?
- No. Parsing and rewriting both happen in your browser using Papaparse — your file never leaves your device. Even multi-million-row CSVs stay local.
- What does 'clean' actually do?
- Each toggle is independent: trim whitespace from every cell, drop rows where every cell is empty, remove duplicate rows (whole-row match), and normalise CRLF / CR line endings to LF. Toggle off anything you don't want.
- Will it preserve quoted fields with commas inside?
- Yes. The parser is RFC-4180 compliant and round-trips quoted fields, embedded commas, embedded newlines and `""` escaped quotes exactly. Output is re-quoted only where required.
- What happens to the header row?
- The header row is treated like any other row — trim and quoting fixes apply. We don't drop or reorder headers automatically.
- Which delimiters are supported?
- Comma, semicolon, tab and pipe. The cleaner sniffs your delimiter on import and lets you override it; the output uses whichever delimiter is selected.
- How big a file can I clean?
- There's no fixed cap. A few hundred MB and several million rows usually work on a modern laptop. The browser will warn long before anything bad happens.
- Does it remove duplicates by one column or the whole row?
- Whole row by default — every cell must match for a row to count as a duplicate. Use the dedicated 'Remove duplicates' tool if you want to dedupe by a specific key column.
- Why does my file look smaller after cleaning?
- Almost always because empty rows or duplicate rows were removed. The footer under the preview reports exactly how many rows were dropped.
- Will Excel still open the cleaned file?
- Yes. The output is plain UTF-8 CSV with LF line endings, which Excel, Numbers, Google Sheets and Power BI all import without trouble.
- Is it really free with no signup?
- Yes — every Files & Data tool here is free, no signup, no row limit, no watermark.